CN107068063A - Display device, pixel cell and its driving method - Google Patents

Abstract

The present disclosure relates to a pixel unit and a control method thereof, wherein the pixel unit includes: a driving unit, configured to generate a driving current according to a data signal under the control of a scan signal; a first light emitting unit connected to the driving unit , used to emit light under the drive of the drive current output by the drive unit; the switch unit, connected to the drive unit, used to conduct under the control of the light-emitting control signal to transmit the drive current; and the second light-emitting unit, connected to the switch unit, Used to emit light under the drive of the drive current output by the switch unit. The present disclosure can reduce pixels with low grayscale Mura defects and improve the display effect.

Description

Display device, pixel unit and driving method thereof

technical field

The present disclosure relates to the field of display technology, in particular, to a display device, a pixel unit and a driving method thereof.

Background technique

With the rapid development of display technology, various display devices have been applied to many fields. Compared with other display technologies, OLED (Organic Light-Emitting Diode, Organic Light-Emitting Diode) has the advantages of self-illumination, high contrast, wide color gamut, and low power consumption, and is considered to be the development direction of a new generation of display technology.

In the existing display technology solutions, taking the OLED display device as an example, due to the differences in the threshold voltage and mobility of each TFT (ThinFilm Transistor, Thin Film Transistor) in multiple pixel units, the uniformity of the IV characteristic curves of different TFTs Therefore, the output currents of different TFTs under the same data signal are different, resulting in inconsistencies in the driving current flowing through each pixel unit, resulting in different luminance of each pixel unit, and further resulting in a relatively poor brightness uniformity of the organic light emitting diode display device. Poor, similar problems exist in other types of display devices.

Because it is easier for the human eye to see the difference in luminous brightness at low gray scales, as shown in Figure 1, different positions of the display screen at low gray scales display uneven brightness, so low gray scale Mura defects are easily formed under the existing technical solutions , affecting the display effect. Similarly, similar problems may also exist in other types of display devices.

It should be noted that the information disclosed in the above background section is only for enhancing the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to those of ordinary skill in the art.

Contents of the invention

The purpose of the present disclosure is to provide a display device, a pixel unit and a driving method thereof, so as to overcome one or more problems caused by limitations and defects of related technologies at least to a certain extent.

According to an aspect of the present disclosure, a pixel unit is provided, including:

a driving unit, configured to generate a driving current according to a data signal under the control of the scanning signal;

a first light emitting unit, connected to the driving unit, for emitting light under the drive of the driving current output by the driving unit;

a switch unit, connected to the drive unit, for conducting under the control of the light emission control signal to transmit the drive current; and

The second light emitting unit is connected with the switch unit and used to emit light under the drive of the driving current output by the switch unit.

In an exemplary embodiment of the present disclosure, the drive unit includes:

The first transistor has a first terminal, a second terminal and a control terminal, the control terminal of the first transistor receives the scan signal, and the first terminal receives the data signal;

The second transistor has a first terminal, a second terminal and a control terminal, the control terminal of the second transistor is connected to the second terminal of the first transistor, the first terminal is connected to the first voltage terminal, and the second terminal is connected to the first voltage terminal. The first light emitting unit is connected to the switch unit;

The first capacitor is connected between the second terminal of the first transistor and the first terminal of the second transistor.

In an exemplary embodiment of the present disclosure, the switch unit includes:

The third transistor, the third transistor has a first terminal, a second terminal and a control terminal, the control terminal of the third transistor is used to receive the light-emitting control signal, the first terminal and the second terminal of the second transistor The second end is connected with the second light emitting unit.

In an exemplary embodiment of the present disclosure, the first light emitting unit and the second light emitting unit are respectively a first pixel region and a second pixel region of a sub-pixel, and the first pixel region and the second pixel region The two-pixel area can be arranged vertically, horizontally or interpolated.

According to one aspect of the present disclosure, there is provided a display device including the pixel unit described in any one of the above example embodiments.

In an exemplary embodiment of the present disclosure, the display device further includes:

a source driver, configured to generate the data signal;

a signal compensation unit, connected to the source driver, for compensating the data signal;

a data signal line, connected to the signal compensation unit and the driving unit, for inputting the compensated data signal to the driving unit;

a gate driver, configured to generate the scan signal;

a scanning control line, connected to the gate driver and the driving unit, for transmitting the scanning signal to the driving unit;

a control signal generating unit, configured to generate the lighting control signal; and

The light emission control line is connected with the control signal generating unit and used for transmitting the light emission control signal to the switch unit.

In an exemplary embodiment of the present disclosure, compensating the data signal includes:

comparing the grayscale corresponding to the data signal with a preset threshold;

When the grayscale corresponding to the data signal is smaller than the preset threshold, the data signal is increased to match the gamma curve of the pixel unit.

In an exemplary embodiment of the present disclosure, generating the lighting control signal includes:

comparing the grayscale corresponding to the data signal with a preset threshold;

When the gray scale corresponding to the data signal is greater than or equal to the preset threshold, the light emission control signal is generated to turn on the switch unit.

In an exemplary embodiment of the present disclosure, the preset threshold is 127.

According to one aspect of the present disclosure, there is provided a pixel unit driving method for driving the pixel unit according to any one of the above example embodiments, the driving method comprising:

receiving a data signal, and comparing the gray scale corresponding to the data signal with a preset threshold;

When the gray scale corresponding to the data signal is smaller than the preset threshold, the switch unit is turned off by the light emission control signal and the data signal is increased to match the gamma curve of the pixel unit;

When the gray scale corresponding to the data signal is not less than the preset threshold, the switch unit is turned on by the light emission control signal.

According to the pixel unit and its driving method in this exemplary embodiment, on the one hand, by dividing the pixel unit into a first light emitting unit and a second light emitting unit, the first light emitting unit and the second light emitting unit are controlled by the switch unit under the control of the light emitting control signal. For the light emission of the two light emitting units, only the driving current may be supplied to the first light emitting unit at low grayscale to make only the first light emitting unit emit light; on the other hand, the driving current is generated according to the data signal to drive the first light emitting unit and/or Or the second light-emitting unit emits light, and the driving current supplied to the first light-emitting unit can be increased by increasing the data signal at low gray levels to match the gamma curve of the pixel unit, thereby reducing the number of pixels with low gray-level Mura defects , to improve the display effect.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the disclosure and together with the description serve to explain the principles of the disclosure. Apparently, the drawings in the following description are only some embodiments of the present disclosure, and those skilled in the art can obtain other drawings according to these drawings without creative efforts.

FIG. 1 shows a schematic diagram of the bad phenomenon of low grayscale mura formed by OLED display devices in the prior art solution;

Fig. 2 shows a schematic block diagram of a pixel unit according to an exemplary embodiment of the present disclosure;

Fig. 3 shows a schematic structural diagram of a pixel unit according to an exemplary embodiment of the present disclosure;

FIG. 4 shows a schematic diagram of a pixel circuit structure according to an exemplary embodiment of the present disclosure;

Fig. 5 shows a schematic top view of a single sub-pixel of a pixel unit according to an exemplary embodiment of the present disclosure;

Fig. 6 shows a schematic top view of a single sub-pixel of a pixel unit according to another exemplary embodiment of the present disclosure;

Fig. 7 shows a schematic top view of a single sub-pixel of a pixel unit according to yet another exemplary embodiment of the present disclosure;

Fig. 8 shows a schematic block diagram of a display device according to an exemplary embodiment of the present disclosure;

FIG. 9 shows a flowchart of a driving method for driving the pixel units in FIGS. 2 to 7 according to an exemplary embodiment of the present disclosure; and

FIG. 10 shows a schematic diagram of an improved low grayscale display effect of a display device according to an exemplary embodiment of the present disclosure.

Reference signs:

Gate line Scan control line

Data line Data signal line

CL Luminous Control Line

Vdata data signal

Vscan scan signal

VDD first voltage terminal

T1 first transistor

T2 second transistor

T3 third transistor

EN light control signal

C1 capacitor

VSS common ground voltage

detailed description

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided in order to give a thorough understanding of embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced without one or more of the specific details being omitted, or other methods, components, devices, steps, etc. may be adopted. In other instances, well-known technical solutions have not been shown or described in detail to avoid obscuring aspects of the present disclosure.

Furthermore, the drawings are merely schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and thus repeated descriptions thereof will be omitted. Some of the block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically separate entities. These functional entities may be implemented in software, or in one or more hardware modules or integrated circuits, or in different network and/or processor means and/or microcontroller means.

In this example embodiment, firstly, a pixel unit is provided. Referring to FIG. 2 , the pixel unit may include: a driving unit 210 , a first light emitting unit 220 , a switch unit 230 and a second light emitting unit 240 . in:

The driving unit 210 is used to generate a driving current according to the data signal under the control of the scanning signal;

The first light emitting unit 220 is connected to the driving unit, and is used to emit light under the drive of the driving current output by the driving unit;

The switch unit 230 is connected with the driving unit, and is used for conducting under the control of the light emission control signal to transmit the driving current; and

The second light emitting unit 240 is connected with the switch unit, and is used to emit light under the drive of the driving current output by the switch unit.

According to the pixel unit of this exemplary embodiment, on the one hand, by dividing the pixel unit into a first light emitting unit and a second light emitting unit, the light emission of the first light emitting unit and the second light emitting unit is controlled by the switch unit under the control of the light emission control signal , the drive current can be supplied only to the first light-emitting unit at a low gray scale to make only the first light-emitting unit emit light; on the other hand, the drive current is generated according to the data signal to drive the first light-emitting unit and/or the second light-emitting unit To emit light, the driving current supplied to the first light-emitting unit can be increased by increasing the data signal at low grayscale to match the gamma curve of the pixel unit, thereby reducing the number of pixels with low grayscale Mura defects and improving the display effect.

Next, the pixel unit in this example embodiment will be described in detail with reference to FIG. 3 to FIG. 7 .

Referring to FIG. 3 , in this exemplary embodiment, the sub-pixels can be divided into the first pixel area, that is, the first light-emitting unit 220, and the second pixel area, that is, the second light-emitting unit 240, wherein the anode of the first pixel area is directly connected to In the OLED driving unit 210 , the anode of the second pixel area is connected to the OLED driving unit 210 through the switch unit 230 . In this exemplary embodiment, the anode of the second pixel area may also be directly connected to the OLED driving unit 210, and the anode of the first pixel area may be connected to the OLED driving unit 210 through the switch unit 230, which is also within the protection scope of the present disclosure.

Further, in this exemplary embodiment, when the anode of the first pixel area is directly connected to the OLED driving unit 210, and the anode of the second pixel area is connected to the OLED driving unit 210 through the switch unit 230, the driving unit 210 is connected to the scanning signal, namely Under the control of the signal Vscan on the Gate line, a driving current is generated according to the data signal, that is, the signal Vdata on the Data line, and the first light emitting unit 220 emits light under the drive of the driving current output by the driving unit 210 . When the grayscale to be displayed by the pixel unit is greater than or equal to a preset threshold such as 127, the switch unit 230 is turned on under the control of the light emission control signal on the light emission control line CL to transmit the current output by the driving unit 210 to the second light emission unit 240 , the second light emitting unit 240 emits light under the driving of the driving circuit output by the driving unit 210 . When the gray scale to be displayed by the pixel unit is less than the preset threshold value such as 127, the switch unit 230 is turned off under the control of the light emission control signal, and the drive unit 210 only provides a driving circuit to the first light emitting unit 220, and matches by increasing the driving current. The Gamma curve of the pixel unit, so as to reduce the bad pixels with low grayscale Mura. The anode of the second pixel area is directly connected to the OLED driving unit 210 , and the anode of the first pixel area is connected to the OLED driving unit 210 through the switch unit 230 , which is similar to the above situation, and will not be repeated here.

It should be noted that, in this example embodiment, the preset threshold value of the gray scale may be 127, but the example embodiment of the present disclosure is not limited thereto, for example, the preset threshold value may also be set to 63 or 255 according to actual product requirements, The present disclosure does not specifically limit this.

Next, refer to FIG. 4 , which shows a schematic circuit diagram of a pixel unit according to this example embodiment. In FIG. 4, the drive unit 210 may include: a first transistor T1, the first transistor T1 has a first terminal, a second terminal and a control terminal, the control terminal of the first transistor T1 receives the scan signal Vscan, and the first terminal receives the data signal Vdata; the second transistor T2, the second transistor T2 has a first terminal, a second terminal and a control terminal, the control terminal of the second transistor T2 is connected to the second terminal of the first transistor T1, and the first terminal is connected to the first voltage terminal VDD connected, the second terminal is connected with the first light emitting unit 220 and the switch unit 230; the first capacitor C1, the first capacitor C1 is connected between the second terminal of the first transistor T1 and the first terminal of the second transistor T2. The switch unit 230 may include: a third transistor T3, the third transistor T3 has a first terminal, a second terminal and a control terminal, the control terminal of the third transistor T3 is used to receive the light emission control signal EN, and the first terminal and the second transistor T2 The second end is connected to the second end, and the second end is connected to the second light emitting unit 240, and both the first light emitting unit 220 and the second light emitting unit 240 can be connected to the common ground terminal VSS.

It should be noted that, in this exemplary embodiment, the first transistor and the second transistor may both be N-type transistors, or both may be P-type transistors, or may be partly N-type transistors and partly P-type transistors. This is not particularly limited. Those skilled in the art should understand that the third transistor may be any control device with a switch function, including but not limited to bipolar transistors, field effect transistors, and thin film transistors.

In addition, in this exemplary embodiment, the first end of the transistor is the source, the second end is the drain, and the control end is the gate, but exemplary embodiments of the present disclosure are not limited thereto, for example, the first end of the transistor is also It may be a drain, and the second end may be a source, which is also within the protection scope of the present disclosure.

Further, in this example embodiment, the first light emitting unit 220 ie the first pixel region and the second light emitting unit 240 ie the second pixel region can be arranged vertically, horizontally or interdigitated. Figure 5 shows a schematic top view of the first pixel area and the second pixel area arranged up and down, Figure 6 shows a schematic top view of the first pixel area and the second pixel area arranged left and right, Figure 7 shows the first pixel area region and the second pixel region are a schematic top view of interdigitated arrangement. It should be noted that, in this example embodiment, the first pixel area and the second pixel area may also be set in any other appropriate manner, which is not specifically limited in the present disclosure.

It should be noted that, in this example embodiment, the pixel unit may be an OLED pixel unit, but example embodiments of the present disclosure are not limited thereto, for example, the pixel unit may also be an LCD (Liquid Crystal Display, liquid crystal display) pixel unit, etc. Other pixel units also belong to the protection scope of the present disclosure.

In addition, in this example embodiment, a display device is also provided, and the display device may include the pixel unit in any one of the above embodiments. 8, the display device 800 may also include: a source driver 810, a signal compensation unit 820, a gate driver 830, a control signal generating unit 840, and a display panel 850. In addition, the display device 800 may also include a data signal line DL, a scan control line SL, and a light emission control line CL. Each unit in the display device 800 will be described in detail below.

In this exemplary embodiment, the source driver 810 is used to generate a data signal; the signal compensation unit 820 is connected to the source driver 810 for compensating the data signal; the data signal line DL is connected to the signal compensation unit 820 and the driving unit for Input the compensated data signal to the driving unit; the gate driver 830 is used to generate the scanning signal; the scanning control line SL is connected to the gate driver 830 and the driving unit, and is used to transmit the scanning signal to the driving unit; the control signal generating unit 840, used to generate a lighting control signal, the lighting control line CL is connected to the control signal generating unit 840, and used to transmit the lighting control signal to the switch unit.

Since the display device 800 includes the above-mentioned pixel unit, and the pixel unit is divided into a first light-emitting unit and a second light-emitting unit, the gamma of the pixel unit can be matched by increasing the driving current supplied to the first light-emitting unit at a low gray scale. Mura curve, so that the display device 800 can reduce the pixels with low grayscale Mura defects, and improve the display effect. FIG. 10 shows a schematic diagram of the effect of the display device improved according to the technical solution of this example embodiment. It can be seen from FIG. 10 that, compared with the display screen of the prior art in FIG. 1 , at low gray levels, The brightness uniformity of the display screen is good, and the low gray scale Mura is improved.

Further, in this example embodiment, compensating the data signal may include: comparing the grayscale corresponding to the data signal with a preset threshold; when the grayscale corresponding to the data signal is smaller than the preset threshold When the threshold is reached, the data signal is increased to match the gamma curve of the pixel unit.

Further, in this example embodiment, generating the light emission control signal may include: comparing the grayscale corresponding to the data signal with a preset threshold; when the grayscale corresponding to the data signal is greater than or equal to the When the threshold is preset, the light emission control signal is generated to turn on the switch unit.

In this exemplary embodiment, the display device 800 may be any product or component with a display function, such as electronic paper, OLED panel, mobile phone, tablet computer, television, monitor, notebook computer, digital photo frame, navigator, etc. The disclosure does not specifically limit this.

It should be noted that: the specific details of each unit in the display device have been described in detail in the corresponding pixel unit above, so details will not be repeated here.

In addition, in this example embodiment, a method for driving a pixel unit is also provided, for driving the pixel unit according to any one of the above example embodiments. The driving method may include:

receiving a data signal, and comparing the gray scale corresponding to the data signal with a preset threshold;

When the gray scale corresponding to the data signal is smaller than the preset threshold, the switch unit is turned off by the light emission control signal and the data signal is increased to match the gamma curve of the pixel unit;

When the gray scale corresponding to the data signal is not less than the preset threshold, the switch unit is turned on by the light emission control signal.

According to the driving method of the pixel unit in this example embodiment, when the gray scale to be displayed by the pixel unit is smaller than the preset threshold, the switch unit can be turned off by the light emission control signal, and the data signal can be increased to match the gamma curve of the pixel unit, Therefore, it is possible to match the gamma curve of the pixel unit at a low gray level, reduce low gray level Mura defective pixels, and improve the display effect.

Specifically, as shown in FIG. 9, when the gray scale to be displayed by the pixel unit is obtained from the data signal is greater than or equal to a predetermined threshold such as 127, the switch unit is turned on, and the OLED drive unit provides driving to the anodes of the first pixel area and the second pixel area. Current; According to the data signal, when the gray scale to be displayed by the pixel unit is less than a predetermined threshold such as 127, the switch unit is turned off, and the OLED drive unit only provides a driving current to the anode of the first pixel area (the second pixel area), and by increasing the driving current To achieve the Gamma curve matching of the pixel unit. Therefore, this example embodiment can reduce the low-gray-scale mura-defective pixel points and improve the display efficiency. In this embodiment, the predetermined threshold may be 127, and the predetermined threshold may also be set to other appropriate values according to actual product conditions, which is not specifically limited in the present disclosure. FIG. 10 shows a schematic diagram of the effect of the display device improved according to the technical solution of this example embodiment. It can be seen from FIG. 10 that, compared with the display screen of the prior art in FIG. 1 , at low gray levels, The brightness uniformity of the display screen is good, and the low gray scale Mura is improved.

Other embodiments of the disclosure will be readily apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any modification, use or adaptation of the present disclosure, and these modifications, uses or adaptations follow the general principles of the present disclosure and include common knowledge or conventional technical means in the technical field not disclosed in the present disclosure . The specification and examples are to be considered exemplary only, with the true scope and spirit of the disclosure indicated by the appended claims.

It should be understood that the present disclosure is not limited to the precise constructions which have been described above and shown in the drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims (10)

1. A pixel unit, characterized in that, comprising: a driving unit, configured to generate a driving current according to a data signal under the control of the scanning signal; a first light emitting unit, connected to the driving unit, for emitting light under the drive of the driving current output by the driving unit; a switch unit, connected to the drive unit, for conducting under the control of the light emission control signal to transmit the drive current; and The second light emitting unit is connected with the switch unit and used to emit light under the drive of the driving current output by the switch unit. 2. The pixel unit according to claim 1, wherein the driving unit comprises: The first transistor has a first terminal, a second terminal and a control terminal, the control terminal of the first transistor receives the scan signal, and the first terminal receives the data signal; The second transistor has a first terminal, a second terminal and a control terminal, the control terminal of the second transistor is connected to the second terminal of the first transistor, the first terminal is connected to the first voltage terminal, and the second terminal is connected to the first voltage terminal. The first light emitting unit is connected to the switch unit; The first capacitor is connected between the second terminal of the first transistor and the first terminal of the second transistor. 3. The pixel unit according to claim 2, wherein the switch unit comprises: The third transistor, the third transistor has a first terminal, a second terminal and a control terminal, the control terminal of the third transistor is used to receive the light-emitting control signal, the first terminal and the second terminal of the second transistor The second end is connected with the second light emitting unit. 4. The pixel unit according to any one of claims 1 to 3, wherein the first light emitting unit and the second light emitting unit are respectively a first pixel area and a second pixel area of a sub-pixel, The first pixel area and the second pixel area are vertically arranged, horizontally arranged or interdigitated. 5. A display device, characterized by comprising the pixel unit according to any one of claims 1-4. 6. The display device according to claim 5, further comprising: a source driver, configured to generate the data signal; a signal compensation unit, connected to the source driver, for compensating the data signal; a data signal line, connected to the signal compensation unit and the driving unit, for inputting the compensated data signal to the driving unit; a gate driver, configured to generate the scan signal; a scanning control line, connected to the gate driver and the driving unit, for transmitting the scanning signal to the driving unit; a control signal generating unit, configured to generate the lighting control signal; and The light emission control line is connected with the control signal generating unit and used for transmitting the light emission control signal to the switch unit. 7. The display device according to claim 6, wherein compensating the data signal comprises: comparing the grayscale corresponding to the data signal with a preset threshold; When the grayscale corresponding to the data signal is smaller than the preset threshold, the data signal is increased to match the gamma curve of the pixel unit. 8. The display device according to claim 6, wherein generating the light emission control signal comprises: comparing the grayscale corresponding to the data signal with a preset threshold; When the gray scale corresponding to the data signal is greater than or equal to the preset threshold, the light emission control signal is generated to turn on the switch unit. 9. The display device according to claim 7 or 8, wherein the preset threshold value is 127. 10. A driving method for a pixel unit, for driving the pixel unit according to any one of claims 1 to 4, characterized in that the driving method comprises: receiving a data signal, and comparing the gray scale corresponding to the data signal with a preset threshold; When the gray scale corresponding to the data signal is smaller than the preset threshold, the switch unit is turned off by the light emission control signal and the data signal is increased to match the gamma curve of the pixel unit; When the gray scale corresponding to the data signal is not less than the preset threshold, the switch unit is turned on by the light emission control signal.